I am playing Trine on OS X and use a PS3 controller. I had to set custom key bindings because the buttons where not set properly by default. When playing the warrior in the beginning of level 2 I get the hint that I can block with my shield when right clicking with the mouse. As I use a controller, I was searching for an option to bind this action to a button of my controller. I could not find it though. Binding all other actions for all characters was working without problems, but I can't find a way to use shield block with my controller. How can I do this?

I assume you're playing the original Trine, not Trine Enchanted Edition? Binding the shield can actually be a bit misleading, as it's actually named "Knight throw" in the game's menu. To find the correct skill, you'll have to click "Next page" in the configuration menu a few times until you'll come across the Knight's skills.

Yes I'm playing original Trine because the Enchanted Edition does not perform so well on my laptop. I could not bind the action to a specific button, but I found out that when moving the right stick on my controller down, the knight does crouch and block. So everything is fine now. I cannot charge though. I bound R2 to it, but it does not do anything. I guess I'll get that skill later in the game?